Age-Depth Model of Lake Soppensee (Switzerland) Based on the High-Resolution 14C Chronology Compared with Varve Chronology

From the 20th International Radiocarbon Conference held in Kona, Hawaii, USA, May 31-June 3, 2009.An age-depth model for laminated sediments of Lake Soppensee is constructed using radiocarbon ages of macrofossils and a depositional model of the OxCal v 4.1 program with the updated IntCal09 data set. The resulting calendar chronology is compared with the varve chronology that was built for this record in a previous study (Hajdas 1993); there is a very good agreement between the 2 approaches. This illustrates the potential of high-resolution 14C dating for construction of reliable, high-resolution calendar timescales for sedimentary records. Based on the age-depth model of this study, the Vasset/Killian tephra found in sediment of Soppensee dates to a calendar age of 9291-9412 cal BP (2-delta range) while the Lachersee tephra dates to 12,735-12,871 cal BP (2-delta range). Precise dating of the Late Glacial boundaries is possible with this chronology but requires more precise correlation between proxies and records than typically practiced.The Radiocarbon archives are made available by Radiocarbon and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform February 202

Estimation of Gas Purity in a CO 2

From the 16th International Radiocarbon Conference held in Gronigen, Netherlands, June 16-20, 1997.Since 1994, a new data-acquisition system with rise-time (RT) based background reduction has been in operation at the Gliwice Radiocarbon Laboratory. During long-term stability tests, we observed large shifts in the RT spectra obtained during various measurement series. These shifts caused important changes in the count rate measured with RT reduction. As a result, we have ascertained that the shifts are the consequence of variable concentration of electronegative impurities. A correction method was considered, using average RT of pulses obtained in coincidence with the muon events, so-called ARTL (average rise time of L pulses), for estimation of the RT of the spectrum's shift. However, radiocarbon dates calculated based on count rates with RT discrimination, which were corrected using this method, are not more precise than traditional 14C dates. Nevertheless, the value of the average coincidence pulse RT is a good indication of sample gas purity.This material was digitized as part of a cooperative project between Radiocarbon and the University of Arizona Libraries.The Radiocarbon archives are made available by Radiocarbon and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform February 202

Estimation of Gas Purity in a CO2-Filled Proportional Counter by Rise-Time Analysis

From the 16th International Radiocarbon Conference held in Gronigen, Netherlands, June 16-20, 1997.Since 1994, a new data-acquisition system with rise-time (RT) based background reduction has been in operation at the Gliwice Radiocarbon Laboratory. During long-term stability tests, we observed large shifts in the RT spectra obtained during various measurement series. These shifts caused important changes in the count rate measured with RT reduction. As a result, we have ascertained that the shifts are the consequence of variable concentration of electronegative impurities. A correction method was considered, using average RT of pulses obtained in coincidence with the muon events, so-called ARTL (average rise time of L pulses), for estimation of the RT of the spectrum's shift. However, radiocarbon dates calculated based on count rates with RT discrimination, which were corrected using this method, are not more precise than traditional 14C dates. Nevertheless, the value of the average coincidence pulse RT is a good indication of sample gas purity.This material was digitized as part of a cooperative project between Radiocarbon and the University of Arizona Libraries.The Radiocarbon archives are made available by Radiocarbon and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform February 202

Variability of trace element concentrations in deposits of the Wolbrom and Otrębowskie Brzegi peatlands: a reflection of an anthropogenic impact

W artykule zaprezentowano analizę geochemiczną profili torfowych z dwóch torfowisk, położonych w Polsce Południowej, dokumentujących przedział czasowy od okresu atlantyckiego (od 4900 BC Wolbrom i od 4200 BC Otrębowskie Brzegi) do czasów współczesnych. Jej wyniki poddano analizie statystycznej z użyciem programu PAST, celem porównania badanych torfowisk pod względem wpływu działalności człowieka oraz położenia w różnych zlewniach, z uwzględnieniem przeprowadzonych wcześniej analiz botanicznych, datowania radiowęglowego i ołowiem-210 oraz analizy składu izotopowego Pb. Koncentracja pierwiastków w badanych profilach torfowych zależała od rodzaju osadu i była mocno zróżnicowana, wahając się w przedziale od wartości niskich, zbliżonych do lokalnego tła geochemicznego, aż do ekstremalnie wysokich (w szczególności w przypadku metali ciężkich, takich jak cynk i ołów). Przeprowadzona analiza porównawcza pozwoliła na zaobserwowanie synchronicznego zapisu lokalnych, jak i regionalnych zmian składu chemicznego w dwóch torfowiskach, różniących się lokalizacją, litologią i rodzajem torfu.A geochemical analysis was conducted on peat cores from two peatlands in Southern Poland that cover a time span from the Atlantic period (from 4900 BC in Wolbrom and from 4200 BC in Otrębowskie Brzegi) to modern times. The results were subjected to a statistical analysis using PAST software. The analysis was conducted taking into account previous botanical analyses, radiocarbon dating and lead-210 dating. The aim was to compare these two study sites in terms of their locations in different basins and anthropogenic activity. Elemental concentrations in the tested peat profiles were dependent on sediment type and their values range between very low (close to geochemical background values) and extremely high – especially in the case of heavy metals, like zinc and lead. The comparative analysis showed a synchronous record of local and regional changes of chemical composition in the two peatlands, which vary in terms of location, lithology and type of peat sediment

Frequency Distribution of Radiocarbon Dates as a Tool for Reconstructing Environmental Changes

From the 19th International Radiocarbon Conference held in Keble College, Oxford, England, April 3-7, 2006.Large sets of radiocarbon dates of 1019 peat, 155 speleothem, and 100 tufa samples, as well as dates of 330 fluvial samples, were investigated in order to estimate environmental variability during the last 16,000 calendar years in Poland. All 14C dating was carried out in the Gliwice Radiocarbon Laboratory, and results are stored in the RoS database. Probability density functions (PDFs) were created by summing up (on the calendar timescale) individual age probability distributions of all dates for different types of material and for different regions of Poland. We used an updated version of the Gliwice Radiocarbon Laboratory calibration program GdCALIB. The 14C dates were calibrated using the IntCal04 calibration curve (Reimer et al. 2004), and results were compared with other paleoenvironmental records. The authors conclude that analyzing PDFs of different types of sediments can be helpful in the qualitative reconstruction of the past environment. The PDF for peat samples primarily reflects paleohydrological conditions; the PDFs for speleothem and tufa samples reflect changes in temperature and humidity, while analysis of the PDF created for fluvial data is in a general agreement with the PDFs constructed for peat samples.The Radiocarbon archives are made available by Radiocarbon and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform February 202

A Data Acquisition System for Proportional Counters at Gliwice

We present here the principal ideas of a new, fully computerized data acquisition system with pulse-rise background reduction, developed in the Gliwice Radiocarbon Laboratory, and our first results. The new system uses a microprocessor-controlled pulse and coincidence analyzer for acquisition of data from 3 of 4 proportional counter sets. The analyzer acquires and stores information on the pulse's amplitudes and rise-times and their coincidence with guard counters and radiofrequency shield. This feature allows us to separate pulses using anticoincidence information and pulse-shape discrimination. The described method of background reduction led to a significant increase in the factor of merit on 2 of 3 counters tested.This material was digitized as part of a cooperative project between Radiocarbon and the University of Arizona Libraries.The Radiocarbon archives are made available by Radiocarbon and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform February 202

A Computer-Based Database for Radiocarbon Dates of Central Andean Archaeology

We established a database of 14C dates from archaeological sites of the Central Andes region of Peru, Ecuador and Bolivia on an IBM PC-compatible microcomputer running on an MS-DOS operating system using software package dBASE IV, version 1.1. Relevant data are stored in three DBF-type database files. The file ANDY.DBF contains information on dates and samples; REFERENC.DBF contains references to relevant publications and CALAND.DBF contains calibrated dates. The total number of records of the ANDY database slightly exceeds 2650.This material was digitized as part of a cooperative project between Radiocarbon and the University of Arizona Libraries.The Radiocarbon archives are made available by Radiocarbon and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform February 202

Timescale for Climatic Events of Subboreal/Subatlantic Transition Recorded at the Valakupiai Site, Lithuania

From the 19th International Radiocarbon Conference held in Keble College, Oxford, England, April 3-7, 2006.Oxbow lake deposits of the Neris River at the Valakupiai site in Vilnius (Lithuania) have been studied by different methods including radiocarbon dating. A timescale was attained for the development of the oxbow lake and climatic events recorded in the sediments. 14C dates obtained for 24 samples cover the range 990-6500 BP (AD 580 to 5600 BC). Medieval human activity was found in the upper part of the sediments. Mollusk fauna found in the basal part of the terrace indicate contact between people living in the Baltic and the Black Sea basins. Mean rates were calculated for erosion of the river and for accumulation during the formation of the first terrace.The Radiocarbon archives are made available by Radiocarbon and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform February 202

Absolute Radiocarbon Chronology in the Formative Pottery Production Center of Santa Lucía, Cochabamba, Bolivia

Santa Luca is a pottery production site dating to the Formative period (about 1600 BC to AD 200). It is located in the Cochabamba valleys of the eastern Bolivian Andes. The settlement consists of a residential area and a separate workshop area. A peripheral sector of ash mounds was used as refuse sites and burial grounds. The excavations yielded a total of 16 radiocarbon samples from all 3 sectors, which were dated at the Gliwice Radiocarbon Laboratory (Gliwice, Poland). The results from the deepest trench in the workshop sector (Trench 5) provide information for the stratigraphic sequence and help to define spatial and socioeconomic changes at around 600-500 BC with the beginning of the Late Formative or Santa Luca III phase. The 14C dates from Santa Lucía, therefore, contribute to a better definition of the existing regional Formative period phases and finally to a better understanding of the processes during the Formative period in the south-central Andes.The Radiocarbon archives are made available by Radiocarbon and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform February 202

Radiocarbon and Dendrochronological Dating of Logboats from Poland

From the 17th International Radiocarbon Conference held in Jerusalem, Israel, June 18-23, 2000.The earliest dating of samples taken from logboats found in the area of Poland was done at the Gliwice Radiocarbon Laboratory in the late 1970s and early 1980s. After a 10-year break, the study of their chronology was renewed. The 14C dates (56) include all previously published and new, unpublished results obtained during last several years. Here, we discuss and provide probabilistic interpretation of the calendar age of the dated boats. The calibration of 14C dates was done with the OxCal program for dates less than 300 BP, and with the GdCALIB program for all remaining dates. In distribution of calibrated dates we find a lack of samples between the ages of around 800 BC and 300 AD. This result is surprising and differs from results observed for Central Europe. The remaining age ranges, with high frequency of dates, are in good coincidence with similar periods obtained for Central Europe. Tree-ring dating of oak logboats was carried out on 60 growth sequences, dated against standard chronologies defined for the area of Poland. The results of 14C dating and tree-ring analyses give consistent chronologies.The Radiocarbon archives are made available by Radiocarbon and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform February 202